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A Wide and Fast Lens for Mirrorless Cameras: Laowa 15mm f/2 Review

The Laowa 15mm f/2 D-Dreamer Lens. Credit: Alan Dyer

Offering fast f/2 speed and an ultra-wide-angle field of view, the Laowa 15mm ticks the boxes for nightscapes and tracked Milky Way images.

I’m always on the lookout for fast, wide-angle lenses. The Laowa (aka Venus Optics) 15mm D-Dreamer lens caught my eye several years ago when I bought one for my Sony a7III camera. I liked it so much I recently bought another copy for my Canon R mirrorless cameras. The version for Canon RF-mount is what I test here. However, the lens is also available for Nikon Z- and Leica L-mount cameras, as well as Sony E-mount.

The Laowa 15mm f/2 is one of a new generation of lenses made specifically for mirrorless cameras — it will not work on a DSLR camera. The shorter flange distance of mirrorless cameras makes compact yet fast wide-angle lenses possible. This lens is small, especially when compared to its closest DSLR equivalent, the Sigma Art DG 14mm f/1.8. The Sigma is a massive lens weighing more than double the 500-gram weight of the Laowa 15mm – and costing more than double the Laowa’s $750 price.

The Laowa 15mm has a manual aperture ring and a mechanical focus ring with distance marks and a depth of field scale. The lens accepts 72mm filters. Credit: Alan Dyer

Mechanics
The Laowa 15mm has all-metal and glass construction. It feels solid and dense. This is not a cheap “plastic-fantastic” lens, though it does lack weather sealing.

Like all other Venus Optics lenses, the 15mm is manual focus, and has no electrical connection to the camera. Thus, the camera does not record what lens or aperture was used.

That’s a nuisance, although for astrophotography the lens is likely to be used mostly wide open at f/2, or stopped down to f/2.8 or f/4 at most. But you’ll just have to remember what aperture you used.

The lens has a mechanical aperture ring with clicks at every f-stop. The aperture ring can be de-clicked with the flick of a switch on the lens — videographers prefer a smooth click-less aperture adjustment.

While it comes in an attractive gift box, the lens does not come with a pouch or case, a surprising omission for a $750 lens. It does come with a twist-on metal lens hood. The small (for such a wide-angle lens) front element allows it to accept standard 72mm filters with little or no vignetting, a great feature for using the lens with light pollution filters (such as those I tested here) or soft focus “starglow” filters (such as ones I tested here).

Most critically for astrophotography, on my unit the lens proved the sharpest on stars when it was focused all the way to the hard stop at the infinity mark. That makes it easy to focus. The mechanical focus ring turns smoothly and is nicely damped.

This single 1-minute tracked exposure taken with the Laowa 15mm lens at f/2.8 shows its potential for nightscapes with minimal distortion and corner aberrations. Credit: Alan Dyer

Wide and Fast
This is a rectilinear lens, not a fish-eyefisheye. Indeed, the lens is billed as having zero distortion (“Zero-D” being one of its many monikers), so vertical and horizontal lines remain straight and free of any noticeable barrel or pincushion bending. That’s of value when shooting architectural interiors. But as I show above, it’s helpful when shooting nightscapes to keep the horizon flat.

The field of view is about 110° measured diagonally, which translates to a 90° field of view across the long dimension of a full-frame camera, or about 54° wide on a cropped-frame camera. With a camera turned vertically in portrait orientation, the lens will cover a large swath of sky from horizon to zenith.

Blow-ups of the centers of the same scene taken earlier in the evening show softer images at f/2 but quite sharp star images when stopped down to f/2.8. Credit: Alan Dyer

Optics — Centre Sharpness
Wide open at f/2 the Laowa does show some softness to images at the center of the frame. Stars are bloated by spherical aberration. Stop the lens down to f/2.8 and much of that softness goes away, providing good resolution and tighter star images.



The f/2 aperture is useful for subjects where speed is paramount, such as auroras and real-time movies taken at night. But for most astrophoto applications, it’s best to stop this lens down to at least f/2.8, still fast enough for most camera-on-tripod nightscapes, and certainly for longer exposures of the Milky Way taken on a star tracker.

Blow-ups of the corners of the nightscape scene show the level of coma flaring and lateral chromatic aberration at f/2.8, the best aperture for most uses with this lens. Credit: Alan Dyer

Optics — Corner Sharpness
As the above example shows, at f/2.8 the Laowa shows quite tight star images out to the corners, though with some flaring of stars from a mixture of coma and astigmatism, plus some lateral chromatic aberration which adds blue tails to the stars. I did not see any difference from corner to corner, indicating no issues with de-centered lens elements in my unit.

Corner aberrations improve incrementally as the lens is stopped down. The lateral chromatic aberration lessens but never quite goes away even at f/4. Credit: Alan Dyer

What about at f/2? After all, its fast maximum aperture is this lens’s selling point. Fortunately, edge aberrations don’t blow up at f/2. But neither do they go away completely when stopping down. Even at f/4, bright stars retain some slight flaring and blue tails from lateral color. But it takes pixel peeping to see the flaws.

Though the Laowa 15mm is more costly than popular 14mm f/2.8 manual lenses, you do get better optics than in the lower-cost competition, and almost as good as much more expensive lenses (as I show at the end).

Vignetting is quite severe at f/2 but also improves with each step down in aperture. This is a lens trait that can be compensated for in processing. Credit: Alan Dyer

Optics — Vignetting
The Laowa does exhibit a high degree of vignetting, or corner darkening from uneven frame illumination. At f/2 the corners dim by about two f-stops. That’s a lot! By f/4 the field is much more uniformly illuminated, though the extreme corners remain dim.

Unlike optical aberrations, vignetting can be compensated for in processing. In fact, it seems that lens designers today are purposely sacrificing uniform illumination for lower optical aberrations, knowing that vignetting can be fixed “in post” or even in camera.

This shows the lens correction made by Adobe Camera Raw’s lens profile (arrowed). The setting needed to be backed off (to 88 here) to avoid overly bright corners. Credit: Alan Dyer

Adobe software (Camera Raw and Lightroom) has a lens profile for this and several other Venus Optics/Laowa lenses,, so correcting the vignetting takes just a click to apply the needed brightening to the corners, to “flatten” the field.

Other raw developer programs, notably Capture One, DxO PhotoLab, and ON1 PhotoRAW, do not have a profile for this lens. For these and other programs such as Affinity Photo, vignetting corrections must be dialed in manually and set quite high, especially for images taken at f/2.

Like most wide-angle lenses the Laowa is subject to lens flares and ghost images from internal reflections. Careful composition can avoid the worst of these. Credit: Alan Dyer

Optics — Lens Flares
Like most wide-angle lenses, the Laowa does exhibit some flaring when bright objects (the Moon in these examples) is off-center in the frame or just outside the frame. In the latter case, the image was marred by a large red flare.

Keeping bright light sources out of the frame can be difficult with such a wide lens, so be careful when shooting nightscapes toward the Moon. Only the best and most costly lenses with advanced coatings suppress these internal reflections.

The Laowa 15mm (left) is just for mirrorless cameras. The Rokinon 14mm SP (right) is for DSLRs and has a bulbous front element negating the use of front filters. Credit: Alan Dyer

Laowa 15mm vs. Rokinon 14mm SP
As part of my testing, I compared the Laowa 15mm to a close competitor in focal length, aperture and price, the Rokinon 14mm f/2.4 SP, which sells for $800 to $1,000. This is one of a select few lenses in Rokinon’s Special Performance SP series, all manual focus lenses but with better optics than their more affordable 14mm f/2.8 lenses that are popular with nightscape photographers.

The Rokinon SP is made for DSLRs but can be adapted to mirrorless cameras. It is a large lens which cannot accept front filters and has a maximum aperture of f/2.4. But it is very sharp.

Comparing the centers of tracked exposures, the Rokinon proved the sharper of the pair even when used wide open at f/2.4, compared to the Laowa at f/2.5. Credit: Alan Dyer

Comparing images taken the same night with both lenses, the Laowa was softer at the center of the frame at f/2. But at f/2.5 the Laowa was a close match to the Rokinon with it wide open at f/2.4.

Close, but not equal. The Rokinon was slightly sharper, with very tight, pinpoint star images lacking the residual spherical aberration of the Laowa.

Comparing the corners of the tracked exposures shows both lenses exhibiting aberrations, though with quite different characteristics. Credit: Alan Dyer

At the corners, both lenses showed distorted star images. In the Rokinon, stars were elongated into streaks by astigmatism, but had none of the flaring coma and blue chromatic aberration of the Laowa. Overall, stars looked tighter and sharper in the Rokinon.

The Rokinon 14mm SP is an excellent choice for anyone looking for sharp optics in an ultra-wide lens, especially for use on a DSLR. It has the advantage over the Laowa of offering electrical contacts enabling the lens data to be recorded by the camera in each image’s EXIF metadata.



However, the Laowa 15mm offers two-thirds of a stop faster aperture in a more compact form factor. Those were its prime attractions for me, as I bought it primarily to take stills, time-lapses, and movies of auroras at northern sites.

This compares the Laowa 15mm to the Canon L-series 15-35mm RF at 15mm. While the expensive zoom lens wins, the little Laowa puts in a respectable performance. Credit: Alan Dyer

Laowa 15mm vs. Canon RF 15-35mm
As a final comparison, I shot the same nightscape scene with the Laowa and with Canon’s premium L-series 15-35mm RF zoom lens I tested previously for AGT. The Canon’s maximum aperture is f/2.8, so I used the Laowa with it also set to f/2.8.

Aberrations in the corners are still present in the Canon RF lens but are much less noticeable than in the Laowa. Indeed, the Canon 15-35mm RF exhibits about as low a level of off-axis aberrations as I have seen in such a wide lens, even more remarkable considering this is a zoom lens.

Top mirrorless zoom lenses from Canon, Nikon and Sony are overturning the old wisdom that you must have fixed “prime” lenses for the best image quality.

However, Canon’s 15-35mm RF costs $2,400, so it better be good! The Laowa 15mm offers image quality not far below a top-end lens like the Canon RF, but at a third the price, and with the advantage of its f/2 speed when needed. It is a favorite nightscape lens of several astrophotographers I know. If you are shooting with a mirrorless camera, I can certainly recommend it.

 

Plus: Compact and fast; quite sharp on- and off-axis; accepts 72mm filters
Minus: Some lateral chromatic aberration; high vignetting; no electrical contacts

 

Retail: $750 for Canon RF, Leica L, Nikon Z, and Sony E lens mounts
Website: https://www.venuslens.net/product/laowa-15mm-f2/

 

About Alan Dyer

Alan Dyer is an astrophotographer and astronomy author based in Alberta, Canada. His website at www.amazingsky.com has galleries of his images, plus links to his product review blog posts, video tutorials, and ebooks on astrophotography.

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